1. Field of this Invention
The invention relates to a completely or partially resorbable bone replacement or prosthesis anchoring material on the basis of sintered calcium phosphates.
2. Prior Art
The bone replacement or prosthesis materials presently used are either autologous, homoiologous or heterologous bone transplants or implantable parts of metal, metal compounds, polymers or ceramics. However, all these materials have disadvantages when used for the purpose under consideration. The use of autologous bone grafts implies a double operative procedure combined with considerable postoperative pain for the patient. Homoiologous and heterologous bone grafts, metals, polymers and aluminium oxide ceramic are frequently encapsulated by connective tissue, which prevents bone growth in direct contact to the implant and thus favours loosening of the implant. Further material-dependent reactions are inflammations and foreign-body reactions. In addition, the structure of the above materials as well as that of glass ceramic do not enable resorbable phases to be incorporated, although this would be desirable because it would increase the surface area of the ingrowth region and thus lead to durable implant-bone tissue attachment. Another drawback is to be seen in the fact that re-working of the prosthesis during operation is practically impossible.
While the calcium phosphate ceramic satisfies the requirements of the formation of an intimate bone connection between prosthesis and bearing bone or adjacent bone tissue and that of resorbability of the prosthetic material, this ceramic material is not sufficiently functionally loadable and can be re-worked only to a limited extent.